Article examines theories of three important legal and political theorists working in the time of transformation of legal theory from natural law to utilitarianism, namely Hume, Adam Smith and Bentham. All of them stressed the role of »fictions« in law and understand their theories as an answer to »fictitious« ideas of their opponents, so that their theories could be understood as an attempt to come to terms with »Activity« of natural law theories. While Hume and Adam Smith developed the idea of »unintended consequences« of human actions as an explanation for the functioning of modern society, Bentham's frontal critique of Common Law as existing legal practice laid foundations for utilitarian theory of law and modern legal positivism.Articl...